A wireless communication system typically consists of a plurality of cells served by a number of access points. Typically, the access points are grouped into paging areas to help with a paging process. A mobile station can move within a paging area or from one paging area to another paging area. In general, the movement of mobile station within the communication system is known as mobility of the mobile station. As the mobile station travels, it registers with an access point associated with the location of the mobile station's position. Thus, the location of the mobile station is updated to the communication system and can be later used for other system operations. Also, the location data of the mobile station is constantly recorded as the mobile station moves within the system, and the current location of the mobile station is reported to the system. At some instances, however, the location of the mobile station may be unknown to the communication system because of different modes in which the mobile station travels.
In general, the mobile station operates in at least two modes, namely, a connected or active mode and an idle mode. Mobile stations can also operate in sleep mode, which is similar to idle mode. In the connected or active mode, the mobile station, among other operations, establishes a call or participates in an active communication with another communication device such as another mobile station. If the mobile station moves to a new cell during active mode, the control of the communication with the mobile station is handed over to the new cell. Thus, in connected mode, the location and a serving cell for the mobile station is well known to the communication system.
On the other hand, if there is no active communication, the mobile station switches to the idle mode to conserve battery power. Because of mobility during the idle mode, the communication system may not know the location of the mobile station at the same level of precision as when the mobile station is in the active mode because the mobile station is not in active communication with the network. In idle mode, the location of the mobile station is typically known only when it registers with an access point in a new paging area. Thus, when a communication with the mobile station in idle mode is desired, a paging process is utilized by the communication system to locate the mobile station. The paging process is performed by sending poll messages to all the cells in that paging area. As the communication system grows, the system cost of paging the mobile stations increases because of the additional area and equipment that must be covered by the poll messages.
Conventionally, a paging process broadcasts a paging request to all the access points of a paging area in which the mobile station last registered. This, however, increases the cost for paging and may be an inefficient utilization of the bandwidth since the paging request is sent to all the access points in the paging area. As a result, the paging process uses a large amount of radio resources.
Several approaches have been proposed for the paging process to overcome the aforementioned problems. These approaches, however, focus on the architecture of the communication system. Further, these approaches permit unlimited overlapping of paging areas as well as dynamic changes in the configuration of the communication systems based on the movement of traffic. These architecture based approaches require modifications in the existing communication system and thus, introduce additional implementation costs.
Accordingly, it would be desirable to have an improved method and apparatus to better the signaling traffic and reduce the paging cost in the network by utilizing the existing communication system.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.